When you do not have enough information about something, you may have to guess.

The more information you get, the smaller your guess and the more likely you are to be right.

But there are times when you just cannot get all the information you need and you have to guess.

At other times you may guess because you want to.

Small guess (SG): You can never be sure about the future. Anything you say about the future has to be somewhat of a guess. It is more likely than not that something will happen, it is a small guess (SG).